Signaling system for single-track railroads



N. D. PRESTON.

SIGNALING SYSTEM FOR SINGLE TRACK RAILROADS.

APPLICATION men JULY 8,1916.

1 399 72 5 Patented Dec. 6, 1921.

2SHEETS-SHEET I.

Q I (\l 22 B 9* LL. LL.

INVENTOR M ,9 0

MM Z" "3 ATTORNEY N. D. PRESTON.

SIGNALING SYSTEM FOR SINGLE TRACK RAILROADS.

APPLICATION FILED JULY 8,19l6. .1 ,399,725. Patented Dec. 6, 1921.

2 SHEETS SHEEI 2.

- INVENTOR E. ATTO UNIT NEIL D. PRESLEON, OF RUCHESTER; NEW YDRIYI, AQSIGNOR T0 GENERAL RAILWAY SIGNAL COMPANY, 013 GATES; NEW YORK, A CORPORATION OF NE'W.Y0R

SIGFNAIJIIIG SYEITEM SINGLE-TBA.

CK RAILRGADS.

isoa'ras.

Spccificationof LettersEatent.

Patented Dec. 6, 191%.

Application filed July 8, 1916. Serial No. 103,184.

To all whom it may concern Be it known that I, NEIL D. \PRIESZION, a citizen of the United States, and a resident of the city of Rochester, in the county of Monroe and State ofllew Yorr, have invented a new and useful tlignaling System for Single-Track. Railroads, of which the following is a specification.

This invention relates to signaling systems for railroads, and more particularly to signaling systems for single track: railroads of the typewhich has been termed the absolute permissive block system.

In the absolute permissive block system,

to which this invention more particularly relates, certain signals are governed in one way by trains moving in one direction, and in another way bytrains moving in the opposite direction; and. in order to change the character of the control of these signals in accordance with the direction of movement.

of trains, there have been used in the signaling systems of this type heretofore devised, relays which by reason of the manner in which they are. controlled are commonly called stick relays; and in addition to these stick relays special controlling circuits have been employed so that when a train moves in one direction into a certain track section,

one of these stick relays is energizedand is maintained energized while and so long as this train occupies a certain portion of the stretch of track.

One of the principal objects of this invention is to devise an arrangement and conetruction of parts whereby the funi'ztiou which is performed by a stick relay, in the signaling systems of this type heretofore devised may be simply and efficiently performed by means operated by the movement of'the semaphore arm of the signal itself, subject to the control of a track sec tion adjacent to that signal.

A. further object of the invention is to cevise asignaling system of the general character above mentioned which will be more economical in the consumption of current than the signaling systems using stick re: lavs.

A further obj cctof the invention is to tie vise a signaling system in which. the current for operating the relays and other parts of the system may be derived? from a single source, and in which the parts of the svs tem are so constructed and arranged that the proper operation of the system will not be affected by any temporary interruption of this supply of current.

Other objects and advantages will appear as the description of the invention progresses, and the novel features of the inventionwill, be particularly pointed out in the appended claims.

in describing the invention in detail, ref erence =ishad to the accompanying drawing in which is illustrated a preferred physi cal embodiment of the invention, in which like reference characters designate like parts n the several views, and in which- Figure l is a schematic view of a stretch of single track between two passing sidings, and shows an arrangement of signals suitable for controlling traflic in either direction over this stretch of track;

Fig. 2 is a diagrammatic view showing a portion of the stretch of track shown in F 1g. 1, and illustrating a preferred form of the construction and arrangement of parts {and circuit embodying this invention;

Fig. 3 is an end view of a circuit controller of well known construction used in connection with a semaphore signal op erating mechanism and shows applied thereto one form of an electrically governed circuit controlling device used in the signaling system shown in Fig. 2;

F ig. -1- is a fragmentary plan view, with parts removed, of the electrically governed circuit controlling device shown in Fig. 3 and illustrates more particularly the manner of mounting the solenoid in the supporting bracket hereinafter more fully de scribed;

Fig. 5 is a fragmentary side view looking toward in F ig. 3; and

Fig. 6 is a fragmentary section taken substantially on the line 66 in Fig. 3.

Referring to Fig. 1, there is illustrated a stretch of single track, indicated by a single heavy line, and a passing siding S and S at each end of this stretch of track. The stretch of single track is divided by insulating joints 3 in the usual manner into a number of track sections designated A, B, C, D, E, and F[ the left at the parts as shown cuits for governing the operation of the signals governing trafiic over the stretch of track, a portion of these controlling circuits, together with the other relays being shown in detail in Fig. 2 and more fully described hereinafter. In Fig. 1 there are illustrated signals 5, 6, 7 and 8 for governing traflic from right to left, in the direction indicated by the arrow Y, and signals 9, 10, 11' and 12 for governing traflic from left to right, in the direction indicated by the arrow X. The signals 8 and 9 located at the right and left hand end of the stretch of single track, respectively, are of the type commonly known as an absolute signal, whereas the other signals are of the type commonly known as permissive signals. The characteristics of these different kinds of signals are well known in the art, and for the purpose of understanding this invention it is deemed unnecessary to further discuss the significanoe attached to these different types of signals, or to describe in detail wherein these signals are distinguishable; but in the arrangement shown the absolute signalsS and 9 are made distinguishable from the other permissive signals by reason of the fact that these absolute signals have square ended blades, while the permissive signals have pointed blades.

The general scheme of operation of the signaling system schematically shown in Fig. 1 may be briefly described as follows: The movement of a train in either direction upon the stretch of single track causes all of the signals governing traflic in the opposite directionto assume their biased sto) position that is, if a train enters the track section'A while travelin in the direction indicated by the arrow II, the signals 6, 7 and 8 governing traffic in the opposite direction assume their stop position. As the train progresses along'the stretch of single track these opposing signals governing traflic in an opposite direction are held in their stop position until thetrain passes them; that is, with a train traveling in the direction indicated by the arrow X, the signal 6 will be held in the stop position until the train has entirely passed this signal, the signals 7 and 8 being also held in the stop position in the meantime, the signal 7 will be held in the stop'position until the train entirely passes this signal, and likewise the signal 8 will be held in its stop position until the train has entirely left the track section F. .In this way, when a train enters the stretch of single I track from either end, the entrance of any other train into said stretch'at the opposite end is prevented. Furthermore, when a train enters the stretch ofsingle track traveling in either direction, the signals governing traffic in the direction in which the train is traveling are successively caused'to assume, first,-fa horizontaior stop position, second,

a diagonal or caution position and a. vertical or clear position; that is, with a train traveling in the direction of the arrow X, the signal 9 is in the stop position while this train occupies the track sections A and B, is in the diagonal or caution position while the train occupies the track sections C and D, the signal 10 at this time being in the stop position; and when the train proceeds into the track sections E and F the signal 11 assumes its horizontal or stop position, the signal 10 its diagonal or caution position, and the signal 9 its vertical or clear position. In this way, while one train is passing through the stretch of single track, another train, traveling in the same direction as the first train, may enter said. stretch of track and be properly governed by signals. In this connection it is stated that the control of the signals to the diagonal or caution position is not shown in detail in the diagranv matic illustration in Fig. 2, since various arrangements for causing a signal to assume its diagonal or caution position when the next signal in advance is inthe horizontal or stop position are well known in the art, and if illustrated in Fig. 2 will only serve to unnecessarily complicate the drawing.

In Fig. 2 of the drawing there are shown track sections B, C, D, and E corresponding to the track sections B, C, D and E in Fig. 1, and controlling circuits suitable for governing the signals 6, 7 l0 and 11, also corresponding to the signals 6, 7 10 and 11 in Fig. 1. In Fig. 2, the numerals 1 and 2 designate the track rails of the stretch of single track, the separate rail sections there of being suitably bonded together in the well known manner, and the numeral 3 designates insulating oints interposed in the track rails 1 and 2 and serving to divide the track into the electrically isolated track sections B, C, D and E. At one end of each track section a track battery 4 is connected across the track rails 1 and 2; and at the other end of each track section a track relay is connected across said track rails, the track relays for the track sections B, C, D and B being designated 13, 14;, 15 and 16, respectively. Extending the full length of the track protected by the signaling system is an insulated conductor, commonly termed a common wire and designated 25 in Fig. 2. As is well understood by those skilled in the art of railway signaling this common wire 25 forms a part of one or more controlling circuits extending between different signal locations, and for convenience certain of the circuits hereinafter traced will be traced from the common wire 25 at one point back to this common wire at another point, it being obvious that the common wire serves to complete these circuits.

Associated with each signal is a relay hereinafter termed a line relay, the line relays for the signals 6, 10, 7 and 11 shown in Fig. 2 being designated 17, 13, 19 and 20. Associated with each of thesignalsfi, 10, 71 and 11 is a circuit controlhng devlce operated in conjunction with the operatmg mechanism of the corresponding slgnal, subject tothecontrol of the track relay of the track section adjacent to the corresponding signal in the way more fully explained hereinafter in the description of the operation. While this circuit controlling device may take different forms, and still be capablo of performing the function necessary for the operation of the signaling system as a whole, one simple arrangement is illus-.

trated in Figs. 3 to 6, inclusive, in connection with a circuit controller of well known construction used as apart of a semaphore signal operating mechanism. Since this cir cuit controller of the signal operating mechanism is of well known construction and is clearly shown and described in the Patent to W. K. Howe, 1,150,005, dated August 10, 1915, only such part of this complete circuit controller has been illustrated as is necessary to enable a clear understanding of this invention. Referring to Figs. 3 to 6 inclusive, the circuit controller of well known construction referred to comprises a shaft 30 which, in the manner clearly shown and described in the patentabove mentioned, is connected by suitable gearing (not shown) to the shaft to which the semaphore blade is connected said shaft 30 be ing supported in a frame consisting in part of upper and lower bars 31 and 32 connected by a cross-bar or brace 33 in which the shaft 30 is journaled. For the purpose of controlling the circuits for which the circuit controller is designed, a drum of insulating material 34 is fixed to the shaft 30 and carries suitable contact strips arranged to cooperate with contact springs or fingers, which are secured to blocks 47 of insulating r' material which in turn are secured to the upper and lower bars 31 and 32 by screws 43 (see Fig. 5,) all in the manner clearly shown and described in said patent above mentioned. 1

Referring to the construction of the circuit controlling device embodying this invention, the lefthand part of the entire circuit controller, as viewed in Fig. 5, will be, for convenience, termed the frontor outer end. Looselymounted on the shaft 30 in front of the cross-brace 33 is a drum 35 of wood or other suitable insulating material, a metallic bushing 36 being interposed between said drum 35 and said shaft 30 to avoid wear on said drum. Between the drum 35 and the enlargement or hub at the middle of the cross-brace 33 are two metal lie disks or washers 37, one being preferably fastened to the drum 35; and these washers permit the drum 35 to turn without excessive friction and wear between it and the cross-brace 33. Fastened to the front or outer end face of the drum 35 by screws 39 is a plate 38 which has an integral tongue 40 projecting radially relatively to the drum to a point beyond the circumference of said drum, the outer end portion of said tongue 40 being bent back to extend substantially parallel with the axis of said drum, as clearly shown in Fig. 5. Referring more particularly to Fig. 6, a collar 41 is fixed to the outer end of the shaft 30, as by being pinned thereto, and loosely mounted on said shaft 30 is another collar or sleeve 42 which has a radial notch or recess 43 extending outward from the shaft 30. A pin 44 is fixed in the shaft 30 and is disposed within the recess 43 in the collar 42 so that while the collar 42 may move endwise on the shaft 30, it must turn with said shaft. lnterposed between the collar 42 and the outer face of the plate 38 are two friction disks or washers 45, preferably made of fiber or similar material; and interposed between the collars 41 and 42 is a compression coil spring 46.

Fastened to the upper lefthand insulating block 47, as the circuit controller is viewed in Fig. 3, are two contact fingers or springs arranged'side by side, only one of these contact fingers, designated 49, being shown in Fig. 3. In a similar way two contact fingers arranged side by side are secured to the lower lefthand insulating block 47. Fastened in any suitable wayto drum 35, as by screws, is a metallic contact strip 51 extending longitudinally of the drum 15 a sufficient distance to make electrical contact with both of the contact fingers 50; and in a similar way a contact strip 52 is secured to said drum 50 so as to make contact with the two contact fingers 49, when the drum has been moved to its operated position, as explained hereinafter. Secured to the up per righthand insulating block is a single contact finger 53, and secured to the lower righthand insulating block 47 is a single contact finger 54. A contact strip is fastened to the drum 15 in position to make electrical connection between the contact fingers 53 and 54 in certain positions of the drum 15 as more fully explained hereinafter.

A bracket, designated as a whole by the letter R, is fastened to the upper and lower bars 31 and 32 by bolts 56, and this bracket comprises a web portion 57, an upper horizontally projecting lug 58 and a lower horizontally projecting lug 59, between which a solenoid 60 is fastened in any suitable way, the web portion 57 being curved, as clearly shown in Fig. 4, so as to conform to the outer curvedsurface of said solenoid. To the bracket ll below the solenoid 60 a detent or latch 6.1 is pivotally mounted between its plunger-63 of the solenoid 60 is bifurcated at its lower end and is provided with a transverse pin 64L which passes through a slot 65 in the latch 61 near one end thereof. The other end or nose of the latch 61, strikes a stop 66 fixed to the bracket B so as to limit the downward movement of the plunger 63, and the other end of said latch. Normally thesolenoid 60 is deenergized and the parts are moved to the position shown in Fig 3 by the weight of the plunger 63 and the latch 61, so that the nose of the latch 61 extends across the path of movement of the outer end'portion of the tongue 4-0 of the plate 38, as clearly shown in Fig; 3. The inner edge of the bracket R is provided with a flange 67 which is substantially concentric with'the axis of the shaft 30 and is formed with upper and lower stops or shoulders 68 and 69, which are positioned so as to be struck by the tongue 4 :0 in the two extreme positions of the drum 35.

The operation of the circuit controlling device, shown in Figs. 3 to 6, inclusive, is as follows When the semaphore arm, which is operatively connected to the shaft 30, is permitted-to move from an operated posi* tionto its biased position, the shaft 30 is turned counter-cloclnvise, as viewed in Fig. 3, in the direction indicated by the arrow a. The parts'are shown in Fig. 8 in their nor: mal position corresponding to the operated position of the semaphore arm; and in this normal position of the parts the contact strip 51 makes electric contact between the two contact fingers and theconta'ct strip 55 electrically connects the contact fingers 53 and 5 1, whereas the contact strip 52 is not contact with the contact fingers 49. When the semaphore arm moves from an operated position to its biased position and drives the shaft 30 in the direction indicated by the arrow a, it tends to drive the drum 85 in the same direction by reason of the friction between the collar 42 driven by the shaft and the plate 38 secured to the drum 35; but the solenoid is deenergized at the time the semaphore shaft commences its movement toward its biased position, the

latch 61 is-in the position shown in Fig. 3,

' so that the nose of this latch engages the tongueAlO of the plate 38 and prevents the movement of the drum 85 'more than a few degrees, the contact strip 51 maintaining contact with the contact fingers 50 and the contact strip 55 maintaining electrical conneotion between the contact fingers 53 and 54 during this slight angular movement of the 1 drum 35. If the solenoidfiO, however, is energized when the semaphore arm commences to move toward its biased position, the plunger 63 ofthe solenoid 30 is attracted upward and moves'the latch out of the way of the tongue 10, so that the drum 35 is free to turn with the shaft 30 until the tongue 4() strikes the upper shoulder or stop (58. During th s movement of the drum 35, the contact strip 51 is moved out of contact with the two contact fingers 50, thereby breaking a circuit pointed out hereinafter in the descnption of the operation. Vhen the drum 35 attains its extreme operated position, in which the tongue l0 engages the stop 68, the contact strip 52 is brought into contact with the two contact fingers 19, thereby establishing a circuit pointed out hereinafter. Obviously, the drum will be held in its operated position so long as the semaphore arm of the signal remains in its biased position, and consequently, the circuit including the contact fingers l9 and the contact strip 52 will be closed while and so long as the semaphore arm remains in its biased position. After the drum 34: has been moved by the shaft 3!) far enough so that the tongue 40 is above the latch 61, if the latch 61 is in position to permit the movement of the drum 35, the contact strip 55 breaks contact with the coin tact spring 54, thereby breaking the circuit through the solenoid (i0. as explained more fully hereinafter, so that the latch 61, if it has been raised, may drop to its normal position without affecting the further movement of the drum The circuit for encrgizing the solenoid 60, being broken shortly before the shaft 30 finishes its movement, is interrupted during the time the somaphore arm remains in its biased position. regardless of whether or not the drum 35 has moved and the circuit including the contact fingers 49 is closed; and in this way, as will be made more clear hereinafter, the current necessary for the operation of the signaling system is decreased. During the next movement of the semaphore arm from its biased position to an operated position, the shaft 30 is rotated in the direction opposite to that indicated by the arrow (1, and the drum 35 is carried by this movement of the shaft 30 back to its normal position, as shown in Fig. 3, the tongue 10 snapping by the latch 61, and engaging the lower stop 69 to arrest the movement of said drum 15. The angle between the upper and lower steps 68 and 69 is preferably determined with reference to the angular movement of the shaft 30 during the movement of the semaphore arm connected thereto from its horizontal position to its vertical or 90 position, so that less than a 15 movement of the semaphore arm will cause suflicient movement of the shaft 30 to move the drum from one extreme position to the other, for the reason which will appear hereinafter In Fig. 2, the circuit controlling device actuated by the semaphore operating mechanism hereinbefore described is shown diagrammatically as consisting of a solenoid and three pairs of contacts; and in this diagrammatic illustration the parts designated 26, 27, 28 and 29 represent the solonoids 60 of the circuit controlling devices associated with the signals 6,10, 7 and 11., respectively. The contact fingers 53 and 54: and the contact strip 55 are replaced in Fi 2 by the pair of contacts illustrated above the corresponding coils 26, 27, 28 and 29, and designated 26 27 28 and 29 a In a similar way the contact fingers 50 and the contact strip 51 are shown in Fig. 2 as pairs of contacts designated 26 27 28 and 29 and contact fingers 419 and contact strip 52 are represented by pairs of contacts designated 26 27 28 and 29 In Fig. 2 the signals and the parts assooiated therewith are shown in the normal position which they assume when no train is present upon any part of the stretch of single track T. Under these conditions, the track relays 13, 14, 15 and 16 and the line relays 17, 18, 19 and 20 areenergized. The circuit for energizing the line relay 18 may be traced as follows: commencing at the common wire 25, conductors and 71, line relay 18, conductor 72, armature in of the track relay 141 in its upper position, conductor 73, contacts 28 conductor 74, armature 15 of a track relay 15 in its upper position, conductors and 76, armature 20 oi the line relay 20, conductors 77 and 7 8, battery 24:, and conductors 79 and 80, back to the common wire 25.

l ron the circuit last traced, it can be seen that the line relay 18 at the signal 10 is controlled by the track relays of the track sections C and D protected b this signal, by the normally closed contacts 28 ot' the circuit controlling device governed by the opposing signal 7, and by the line relay 20, so that it either of the track sections C and D is occupied, or the signal controlling device at the signal 7 is in its operated position, so as to open the contacts 28 or if the line relay 20 is deenergized, the controlling circuit for the line relay 18 is broken. There is also a normally open shunt for the armature 20 of the 1 line relay 20 comprising conductors 76 and 81, contacts 29 of the circuit controlling device associated with the signal 11, and conductors 82 and 77, so that the line relay 20 be deenergized and its armature 20 may be in its lower position, and yet the controlling circuit for the line relay 18 may be closed as liar as the control of that circuit by the line relay 20 is concerned, providing the circuit controlling device at the signal 11 is operated so as to close the contacts 29 All of the controlling circuit for the line relay-at the signal 9 is not shown in Fig. 2, but since this controlling circuit is the same as that already described in connection with the line relay 18, it may be easily traced as follows: commencing at the common wire 25, through the line relay at the signal 9, through a front point of an armature of the track relay connected to the track section A, thence along conductor 86, contacts 26 closed, conductor 87, armature 13 of the track relay 13 in its upper position, conductors 88 and 89, armature 18 of the line relay 18 in its upper position, conductors 90 and 91, battery 22, and con ductors 92 and 70, back to the common wire 25. The shunt for the armature 18 comprises conductors 89 and 98, contacts 27 and conductors 94 and 90.

The controlling circuit for the line relay at the signal 11 may or may not be exactly the same as the controlling circuit for the line relay 18, since the manner of control of the signal 11 may depend upon the mare ner of control of the signal 12, in such a way as to facilitate and properly protect train movements upon and by the siding 8 but since the control of these train movements may be accomplished in different ways, and since the control of the signals between passing sidings alone is sufficient to illustrate the features, utility and the operation of the signaling system embodying this invention, it is assumed for simplicity that the controlling circuit for the line relay 20 at the signal 11 is governed only by the track relays connected to the track sections E and F, so that this controlling circuit may be traced as follows: commencing at the common wire 25, conductors and line relay 20, conductor 84, armature 16 oi. the track relay 16 in its upper position, conductor 85, thence through a front point of an armature of the track relay connected to the track section F, and thence through a battery back to the common wire 25.

The controlling circuits for the line relays of the signals 6, 7 and 8 governing tranic in the opposite direction are the same as those for the signals 9, 10 and 11, but only one of these controlling circuits, namely,

the controlling circuit oi the line relay 19 for the signal 7 is illustrated entirely, this controlling circuit being as follows: Commencing at the common wire 25, conductors 95, 96 and 97, line relay19, conductor 98, armature 15 of the track relay 15 in its upper position, conductor 99, contacts 27 of the circuit controlling device at the opposing signal 10 in their closed position, conductor 100, armature 1& of the tract; relay 14: in its upper position, conductors 101, 102, armature 17 of the line relay 17 at the signal 6 in its upper position, conductor 103, battery 21, and conductors 1041 and 105 back to the common wire 25; The shunt for the armature 17 of the line relay 17 consists of conductor 106, contacts 26 and conductors 107 and 102.

As explained hereinbefore in connection with the control of the signal 11, it is assumed that the line relay 17 at the signal 6 is controlled only by the track relays of the track sections A and B, that part of the controlling circuit for the line relay 17 shown in Fig. 2 being as follows: commencing at the common wire 25, conductors 105, 108 and 109, line relay 17, conductor 110, armature 13 of the track relay in its upper position, conductor 111, from whence this controlling circuit passes through a front point of an armature of'the track relay connected to the track section A, through a battery and back to the common wire 25.

The line relay at the signal 8 is controlled by the line relay at the signal 7 and by the track relays of the track sections E and F in the same way as pointed out in connection with the line relay 18, that part of the controlling circuit of the line relay at the signal 8 which is shown in Fig. 2 being as follows: commencing at the common wire 25, through said line relay at the signal 8, a front point of an armature of the track relay connected to the track section F, conductor 112, contacts 29 of the circuit controlling device associated with the opposing signalll, conductor'113, armature 16 of the track relay 16 in its upper position, conductors 114' and 115, armature 19 of the line relay 19 in its upper position, conductor 116, battery 23, and'conductors 117 and 95, back to the common wire 25. The shunt for the armature 19 comprises conductor 118, contacts 28 of the circuit controlling device associated with the signal 7, and conductors 119 and 115. I

Each line relay controls its corresponding signal and since these controlling circuits are the same an explanation of one will suffice for all. The controlling circuit for the signal 10 may be traced as follows: commencing at the battery 22, conductors 91, 90 and 120, armature '18 of the line relay 18 in its upper position, conductor 121, operating mechanism of the signal 10 (not shown) and conductors 122, 123, and 92,

back to the battery 22. In this connection attention is again called to the fact that while the controlling circult for the signal WhlCll 18 shown in Flg. 2 is only sullicient for operating that signal to one operated position, asthe 90 or proceed position, in practice sultable arrangements are made, such as by the use of a polarized line circuitand polarized line relays, whereby each signal is caused to assume a 45 or caution position when the signal next ln advance governing traffic in the same direction is in ts horlzontal or'stop position; but since this controlof the signals to their caution position is well known in the railway sig naling art, it 'is not illustrated in Fig. 2, as

it would merely serve to complicate the illustration.

The controlling circuit for the solenoid (30 of the circuit controlling device associated with the signals 6, 7, 10 and 11 is the same in each case and tracing one of these controlling circuits will be sufiicient for a clear understanding of this invention. The circuit for energizing the solenoid 27 at the signal 10, which corresponds to solenoid (50 shown in Figs. 3 to G inclusive, may be traced as follows: commencing at the battery conductors 91, 90, 120 and 12a, armature 11 of the track relay 14 in its lower position, conductor 125, contacts 27 closed, conductors 126, solenoid 27, and conductors 127, 123 and 92, back to the battery 22.

Operation: Assume that no train is present upon any portion of the track illustrated in Fig. 1, and assume that a train traveling from the left to right, in the direction indicated by the arrow X, enters the stretch of single track T. lVhen this tra n enters the track section A it shunts the track relay connected to this track section in the way which will be clearly understood by those skilled in the art of railway signaling, and the dropping of the armaturcs of this track relay interrupts the controlling circuit for the line relay governing signal 9, thereby causing the signal 9 to assume its biased or stop position. Also, the dropping of the armature of the track relay connected to the track section A interrupts the controlling circuit for the line relay 17 at the signal 6, so that this line relay 17, being deenergized, causes the signal (3 to assume its biased or stop position. The dropping of the armature 17 of the line relay 17 inter rupts the controlling circuit for the line relay 19 at the signal 7, thereby causing the signal 7 also to assume its stop position.

phore arm of the signal (3 is moving toward its biased position, so that the contacts Elli, which correspond to the contact fingers l1) and the contact strip 52, remain open. For the same reason, the contacts 28 remain open, and the deenergization of the line relay 19 and the dropping of its armature 1.)

interrupts the controlling circuit for the line relay at the signal 8, thereby causing the signal 8 to assume its stop position.

From the foregoing it can be seen that when the train under consideration enters the track section A, the opposing signals governing trailic in the opposite direction, namely, signals 6, 7 and 8 are caused to assume their biased or stop position, so as to prevent the entrance of any other train traveling from right to left into the track section T, and also blocking the movement from right to left of trains then occupying the stretch of single track toward the train under consideration, in case, as 'for instance, two trains moving in opposite directions should happen to pass the signals 9 and 8 simultaneously, or in case a train should pass from any intermediate siding on to the stretch of single track.

As the train under consideration passes from the track section A into the track section B, the track relay 13 is shunted. The dropping of the armature 13 0ithis track relay opens another break in the controlling circuit for the line relay at the signal 9, thereby holding said signal 9 in its stop position. The dropping of the armature 1o of the track relay 13 opens another break in the controlling circuit for the line relay 17 thereby maintaining said line relay deenergized and the signal 6 in its stop position. The armature 13 of the track relay 13 closes the normal open break in the circuit for energizing the solenoid 26, but since the signal 6 is in its horizontal position, the contacts 26 which correspond to the contact fingers 53 and 54L and the contact strip 55 shown in Figs. 3 and 5, are open, and consequently the solenoid 26 is not energized. The energization ott the solenoid 26 at this time would not affect the operating of the signaling system, since it would cause merely an idlemovement of the latch 61, but it is apparent that there is a valuable saving in the amount 01 current consumed for the reason that, instead of maintaining the solenoid 26 energized duringthe time the train occupies the track section B, the solenoid 26 is not energized at all.

As the train under consideration progresses and entersthe track section G, the

track relay 14 is shunted and its armatures drop to their lower position. The dropping of the armature 14. makes another break in the controllin circuit for the line relay 19 at the signal so; that, when the line relay 1? is reenergized, the signals 7 and 8 will nevertheless be held in their stop position.

The dropping of the armature 14: of the track relay 1 1 interrupts the controlling circuit for the line relay 18, thereby causing the signal 10 to assume its stop position. The dropping of the armature 14: of the track relay it, which occurs at the same time or a little before the semaphore arm of the signal 10 commencesits movement toward its biased position, closes the circuit for energizing the solenoid 27, and in the manner hereinbefore described, the energization of this solenoid 27 raises the latch 61 and permits the drum 35 to turn. as the semaphore arm moves toward its blased pos1t1on. T his circuit for energizing the solenoid 27 is maintained 'until the signal 10 has moved to a point a few degrees below its diagonal or 415 position, whereupon the contact finger 54 breaks contact with the contact strip 55 and opens the circuit through the solenoid 27. The contacts 21 which correspond to the contact lingers 50 and the contact strip 51 shown in Fig. 3, are opened by this movement of the circuit controlling device to its operated position and make a still further break in the controlling circuit for the line relay 19, for the purpose more fully explained hereinafter. The contacts 27 which correspond to the contact fingers 49 and the contact strip 52 shown in Fig. 3, are closed by the movement of the circuit eontrollingdevice to its operated position and established the shunt for the armature 18 of the line relay 18, so that although the line relay 18 is deenergized, the line relay at the signal 9 may be energized as soon as the train under consideration has entirely left the track sections A and B, so as to permit another train traveling from left to right to follow the first train. As explained hereinbefore, the signal 9 inprac'tice would assume a diagonal or caution position at this time, and would inform the engineer of the following train that another train traveling in the same direction was only a short distance ahead. When the train under consideration entirely leaves the track sections A and B the controlling circuit for the line relay 1? is reestablished, thereby permitting the signal 6 to assume an operated position, so that this signal 6 may permit the train under consideration to change the direction of its movement andreturn to the siding S, suitable controlling means being provided in connection with the signal 6 to prevent said signal from giving an improper indication in case another train is immediately following. i

As the train under consideration passes from the track section (1 into the track section D,the signals 1 and 8 remainin their stopposition and the signallO also is held in'its stop position. As the train further progresses and enters the track section E, the track relay 16 is shunted; and the dropping of the armature 16 of the track relay 16 keeps the line relay at the signal 8 deenergized, thearmature 16 causes the deenergization of the line relay 20 and the movement of the signal 11 to its stop position, and the armature 16 causes the energization of the solenoid 29, and the operation of the circuit controlling device at the signal 11, in the same manner as hereinbefore described in connection with the signal 10, so that after the train under consideration has entirely left'the track sections C track.

and D,'the signallO may assume an oper ated position in spite of the fact that the line relay 20 is de'e'nergized. lVhen the train has entirely left the track sections C and D, the signal 7 is permitted to assume an operated position, providing another following train has not entered the stretch of single As the train under consideration passes through the track sections E and F the signals 8 and 11 are held in their stop position; but as soon as the train has entirely left this track section, the signal 11 may assume an operated position, and the sig nal 8 may also assume an operated position, providinganother following train has not entered the stretch of single track.

The operation of the signals for a train movement from right to left in the direction indicated by the arrow Y, is like that hereinbefore described in connection with a train movement from left to right and can be clearly understood without further detailed description.

The purpose of the contact fingers 50 and the contact strip 51, which are normally in electrical contact, is to check the operation of the circuit controlling deviceand assure the return of this device to its normal position after it has operated. To illustrate, it might happen for some reason that after the drum has been turned in the direction indicated by the arrow a in Fig. 3 to its' operated position, it might fail to return to its normal or initial position when the semaphore arm controlling it assumed an operated position. Such a failure of the circuitcontrolling device would produce an objectionable condition inthat the shunt for thev armature of the corresponding line relay would be closed regardless of whether or not it were proper, to do so; and one objectionable condition resulting from this failure above'mentloned of the circuit controlling device would be to permit two trains traveling in opposite directions to enter the stretch of single track, as for instance, if the failure above mentioned occurs in connection with the circuit controlling device 1 at the signal 10, the signal 9 would not as- '50 sume its biased position when a train entered the stretch of single track at the righthand end. This objectionable condition cannot occur, however, in the construction and arrangement described, since, while the circuitcontrolling device at the signal 10 is in its operated position, the contacts 27 are'open and maintain the line relay 19 deenergized regardless of whether or not the track sections C and D are occupied. sequently, after a train has passed through Conthe stretch of single track in the direction froinleft to right and placed the circuit controlling device at thesignal 1.0 in its operated position, the opposing signal 7 and also the opposing signal 8 cannot assume an operated position until said circuit controlling device at the signal 10 has returned to its initial or normal position. This arrangement of the contacts 27 in the controlling circuit for the line relay 19 does not interfere with the ordinary or proper operation of the system, for the reason that when a train traveling from left to right, after operating the circuit controlling de vice at the signal 10, leaves the track sections C and D, the circuit controlling device will, under normal conditions, return to its initial position as the semaphore arm of the signal 10 assumes its operated position, in the manner and for the reason hereinbefore explained, so that, under normal operatin conditions, when neither the track section 6 nor the track section D is occupied, the signal 7 may assume an operated position behind a train traveling from left to right.

It should be noted that the circuit controlling device at each of the signals 6, 7 10 and i1 is operated by a train movement in one direction only; that is, referring to the circuit controlling device at the signal 10, this device is operated by a train moving from left to right, but is not operated by the train moving from right to left. In one case, that is, with the train moving from right to left, the solenoid 27 is not energized at all whereas with a train moving in the opposite direction the solenoid 27, although it is energized is energized only temporarily during part of the movement of the semaphore arm of the signal to its operated position. In this way there is a material saving in the amount of current consumed over the current con sumed in systems using stick relays, since in the latter system each stick relay, after it has been energized, must be maintained energized for considerable time. In this connection it should also be noted that the shunts for the armatures of the line relays of the signals 6, 7, 10 and 11 governed by the corresponding circuit controlling devices are not closed until necessary for the proper operation of the system. In some cases it is found expedient to apply the absolute permissive block system to a situation where the current for operating some or all of the rehys and signals is derived from a single source, as for instance, where an al ternating current transmission line is used. Under these conditions it may happen, and in fact in the case of alternating transmission line systems it is not an infrequent occurrence, that the supply of current may be temporarily interrupted, due to switching at the central station or other manipulation necessary to satisfy operating requirements. In case the current derived from a single source as explained above, is temporarily interrupted for any reason, all of the relays and signals assume their deenergized position or condition, but in the construction and arrangement shown and described this interruption of current does not affect the proper operation of the signaling system. In the first place, any of the signals which may be in their biased position and which have caused the operation of the corresponding circuit controlling device will remain in their biased position upon the temporary interrupting of the current, and will hold the operated circuit controlling devices in their operated position, so that when the supply of current is reestablished thesame control of signals exists as existed before the current was interrupted. In the second place, the signals which are in an operated position when the supply of current is interrupted, assume their biased position, but since the solenoids 60 of the corresponding circuit controlling devices are also de'c'nergized, there is no operation of the corresponding circuit controlling device. It may happen that the interruption of the supply of current is very brief, so that before there is time for the semaphore arms of the signals which are in an operated position, to assume a biased position, the current is reapplied; and the track relays, being de'e'nergized at this time, are in the position for the solenoids 60 of the circuit controlling devices associated with these signals to be energized, thereby releasing the drum 35. Immediately upon the reestablishing of the supply of current, however, the line relays of these signals are energized, and the semaphore arms of these signals commence to return to the operated position which they previously occupied, thereby restoringthe drums 35 to the initial position. When the current is reestablished, the line relays and the solenoids 60 are simultaneously energized, and the parts are so propoitioned that after the release of the drum 35 by the energization of the solenoid 60, andbefore the drum 35 is moved by the semaphore arm of the corresponding signal far enough to break the electrical connection between the contact lingers 50 and the contact strip 51, so as to prevent the energization of the line relay of the opposing signal, the line relay assoelated with the signal in question would raise its armature controlling the operating circuit of that signal and commence the reverse movement of the drum 35 back to its initial position.

It has been stated hereinbefore that the angle between the stops 68 and 69 is such that the semaphore arm connected to the shaft 30 does not have. to move through an angle of more than 45 to cause the movement of the drum 35 from one extreme position to the other. Also, the length of the contact strip 55 is selected so that it will not break contact with the contact finger 54; until after the semaphore arm of the corresponding signal has moved from its vertical position through the angle which is a little greater than 41-5". The purpose of this arrangement is to permit the operation of the circuit controlling device by the movement of the semaphore arm of a signal from its diagonal or 1-5 position, indicating caution, to its horizontal or zero position, and this arrangement is desirable, since it is important to operate the circuit controlling device in case of a train following another train through the stretch of single track passes a signal in its diagonal. or 415 position. For instance, referring to Fig. 1, two trains traveling from left to right in the direction indicated by the arrow X may occupy the stretch of single track, one train being in the track sections E or F and the other train in the track sections A or B, and in this case the following train in the track section B might properly proceed by the signal 10 which at this time would indicate caution, and in case the following train did so, it is desirable that the circuit controlling device at the signal 10 should be operated, so that the signal 9 might assume an operated position to permit a third train to follow the first two trains as soon as the second train entirely leaves the track sections A and B. As pointed out, the arrangement of the circuit controlling device is such that the movement of a semaphore arm from its 15 posi- I tion to. its Zero or horizontal position would, if the solenoid 60 were energized, move the drum 35 from one extreme position to the other extreme position; and during this movement the contact finger 54 would make contact with the contact strip 55 until the tongue 40 secured to drum 35 had moved to a position above the latch 61, whereupon the circuit through the solenoid 60 would be broken at the contact finger 54-, so as to economize current as explained hereinbefore.

Although I have particularly described the construction of one physical embodiment of my invention, and explained the operation and principle thereof; nevertheless, I desire to have it understood that the form selected merely illustrative, but does not exhaust the possible physical embodiments of the idea of means underlying my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a signaling system for railroads, in combination: a stretch of track divided into track circuit sections; a first signal and a second signal each having an operated posi tion and a biased position and governing traffic over said stretch in the same direction; a circuit for controlling the first signal; means subjected to the same controlling influence as the second signal for controlling the controlling circuit for the first signal position; and means for nullifying the controlling effect or said means, sald last mentioned means comprising a circuit controlling device having a yieldable operating connection to the second signal and adapted to be moved at times by the movement of the second signal toward its biased position, and normally deenergizing electro-magnetic means controlled by a track circuit adjacent to the second signal and acting when said track circuit is occupied to cause the .circuit controlling device to move with the second signal.

2. In a signaling system for railroads, in combination: a stretch of track divided into track circuit sections; a first signal and a second signal each having an operated position and a biased position and governing trafiic over said stretch in the same direction; a circuit for controlling the first signal; means governed by the track circuit sections of a portion of track protected by the second signal for opening aj normally closed break in said circuit when said portion of track is occupied; a normally open shunt for said break in said circuit; a circuit controller for closing said shunt; a normally deenergized electrically controlled device acting when energized to cause the circuit controller to be operated by the movement of the second signal toward its biased position, an energizing circuit for said device controlled by a track circuit adjacent to the second signal, and means associated with said device for interrupting its energizing circuit when the circuit controller has operated.

3. In a signaling system'for railroads, in combination: a stretch of track divided into track circuit sections signals located at intervals along said stretch for governing trafiic in one direction; a line relay associated with each signal and controlled by the track circuit sections of a portion of said stretch protected by that signal; means controlled by each line I relay for governing the corresponding signal; means controlled by each line relay for controlling the line relay of the signal next in the rear and governing traffic in the same direction; electrically controlled means associated with each signal and automatically operated mechanically by that signal when it moves from one position to another position provided atrack circuit section adjacent to that signal is occupied when the signal moves for rendering said last mentioned means associated with the corresponding line relay ineffective to control the line relay of the next signal in the rear, and means operable after said electrically controlled means has operated for cutting off the supply of current thereto in dependently of its track circuit control.

4. In a signaling system for railroads, in combination: a stretch of track divided into track circuit sections; a signal for governing traflic over said stretch; a circuit controlling device tending to assume an operated condition when said signal moves from one position to another position, said device after being operated being held in its operated position so long as said signal remains in its moved position; means for preventing the operation of said device by said signal; means governed by a track circuit section adjacent to said signal for rendering said means ineffective; and means for signaling controlled by said device.

5. In a signaling system for railroads, in combination: a stretch of track divided into track circuit sections; a signal for governing trafiio over said stretch; a circuit controlling device governed by said signal and tending to assume an operated condition when said signal moves from one position to another position, said device after being operated being held in its operated condition so long as said signal remains in its moved position and being automatically restored to its idler position when said signal reverses its movement; electromagnetic means for preventing the operation of said device by said signal; a circuit for controlling said electromagnetic means; means governed by a track circuit section adjacent to said signal for closing said circuit when that track circuit section is occupied; means for interrupting said circuit for said electromagnetic means after said signal has moved from one position to said another position; and means for signaling controlled by said device.

6. In a signaling system for railroads having track circuit sections, in combination: a first signal. and a second signal for governing traflic in the same direction; means tending to cause the first signal to indicate stop when a portion of the track in advance of the second signal is occupied; a device adapted to be operated mechanically by the movement of the second signal toward its biased position for rendering said first means ineflective; electromagnetic means controlled by a track circuit adjacent to the second signal for determining when the operation of said device shall occur; and a circuit for said electromagnetic means controlled by said device.

NEIL D. PRESTON. 

